From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DC36BC4727F for ; Wed, 7 Oct 2020 16:35:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 75334216C4 for ; Wed, 7 Oct 2020 16:35:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="AEEkToo+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727927AbgJGQfo (ORCPT ); Wed, 7 Oct 2020 12:35:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51302 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727234AbgJGQfn (ORCPT ); Wed, 7 Oct 2020 12:35:43 -0400 Received: from mail-pf1-x441.google.com (mail-pf1-x441.google.com [IPv6:2607:f8b0:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B97FDC061755; Wed, 7 Oct 2020 09:35:41 -0700 (PDT) Received: by mail-pf1-x441.google.com with SMTP id a200so1612982pfa.10; Wed, 07 Oct 2020 09:35:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=JlHSp96jwdaBdct47RiHB7NkTtoShuj526Rv157w8ss=; b=AEEkToo+xI/uX/gPobrYsYoRONOlzjQZcIE0nrz9YHQ1ZGPecQ7FBeUaODednrZ66r Mwmk3eQv/BDSWaOhY6s1yF4QpPH/EfBe+3i3WdVI3OqTGPcUkPjjHiuP3hmWGCKQW57d H+YhKHzFNJOqcwaOJhHB9bwXcf9Whdx3swygfwx/JVy4vz7h6Y/CQbQjCvCEfF8fHnOi rCWIVKzrpeUB4we5mZuRXXB+jrg0u8BMlVA2xDQiVnsK3cRwTQJeCsinFEiGl3LUIUCe dF1yttZsf1Uu52piAfRevAhJnqesFErk1QtHPt4gXU1+f3KnpiYrGIxHXc1F8ypYH4qV mDyQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=JlHSp96jwdaBdct47RiHB7NkTtoShuj526Rv157w8ss=; b=PnRk0Fe9iQYgAMgUvfPhU5adFMnJBZBZxAQ+X1vMDeRBlch9gdYv89Z+fC2/wVHBn1 cJx26Ev0ExvHy5LcEBGLHnKMEhfpcjV8m4fRg1qBn5DWfAzT3ld5sEZbkN6SdoGUbR85 MK0YQV8H80GPUZDVEK5mOFlcJtXnKAVNkk0uWB8LK6o5jaCIFrtlYgGffyaOL+Ym9w6s 1cp8fdKAkkXDLyHNyM1dR8hQt5KFb8RHsijz52ni2+TwNOpC1Wd2ow9CjJZWlqQlUKza f/9cWz5aUHrbX+kLdwxwuWzafkm6GxGftipOJMrlriGc6xbR97Y3ZRS5nCfMzH0+mnLV YbYw== X-Gm-Message-State: AOAM532RDJafAQdwdNUklJ1FidS588XxeInNezTfBiZRz0qWTTumFJZh 8JMl9wFnivMC/cwc8MJGL/s= X-Google-Smtp-Source: ABdhPJy8G4BEoqwWZDL52de8879SFellCj8lLZ2IxrsIOhLmYg9xfEnMC/jjiL5K2jlzthqN59LuBw== X-Received: by 2002:a63:5a11:: with SMTP id o17mr3589843pgb.287.1602088541346; Wed, 07 Oct 2020 09:35:41 -0700 (PDT) Received: from Davids-MacBook-Pro.local ([72.164.175.30]) by smtp.googlemail.com with ESMTPSA id q15sm4013229pgr.27.2020.10.07.09.35.40 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 07 Oct 2020 09:35:40 -0700 (PDT) Subject: Re: [PATCH bpf-next V1 3/6] bpf: add BPF-helper for reading MTU from net_device via ifindex To: =?UTF-8?Q?Maciej_=c5=bbenczykowski?= , Jakub Kicinski Cc: Jesper Dangaard Brouer , bpf , Linux NetDev , Daniel Borkmann , Alexei Starovoitov , Lorenz Bauer , Shaun Crampton , Lorenzo Bianconi , Marek Majkowski , John Fastabend References: <160200013701.719143.12665708317930272219.stgit@firesoul> <160200018165.719143.3249298786187115149.stgit@firesoul> <20201006183302.337a9502@carbon> <20201006181858.6003de94@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> From: David Ahern Message-ID: Date: Wed, 7 Oct 2020 09:35:39 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 10/6/20 6:24 PM, Maciej Żenczykowski wrote: > > FYI: It would be nice to have a similar function to return a device's > L2 header size (ie. 14 for ethernet) and/or hwtype. Why does that need to be looked up via a helper? It's a static number for a device and can plumbed to a program in a number of ways.